Open source contributors weigh in on what projects are friendly to the first-time contributor, and the ones not-so-much

The reasons for contributing to open source projects are as diverse as the projects themselves: To garner new skills, add experience, network with peers, or just for fun. Choosing a project that best suits your needs, and one that is friendly to newcomers, however, can be a daunting task. We polled well-known open source contributors for their recommendations, and the best way to start. They also offer advice on which projects to avoid. Here's what they said:
These 7 projects welcome, and encourage new contributors:Drupal: The Drupal open source content management platform offers a vast, international community with a reputation for being friendly and inviting to new contributors. Although I don't contribute to the project, I know a lot of people who do, and I attended (and reported on) DrupalCon 2012 in Denver, Colorado. You don't have to be a seasoned developer to feel comfortable on the Drupal project.

If you haven't tried Drupal, don't let that deter you. Getting started with Drupal is easy, and the Drupal site walks you through the process. If you don't want to provide your own web hosting and you'd like to dive right in and tinker, check out Drupal Gardens. After you set up your account with a user name and password, you can pick your custom URL (rikki.drupalgardens.com in my case), and then select or create a template.
Then you can tweak your site settings while you learn how Drupal sites work.

Not for newbies: Unless you are a seasoned, well-known open source developer with thick skin, avoid the Linux kernel. "It would be like picking up your little league bat and glove and trying to play with the Yankees."
Steven Vaughan-Nichols, technology journalist

Leslie Hawthorn, a community manager at Red Hat, recommends Drupal for the project's "amazing set of newbie resources, from the Drupal Dojo to beginners support IRC channel." The Drupal Dojo site offers training for the Drupal community in an effort to help users "ascend the Drupal learning curve."
Drupal offers excellent documentation for new contributors in the form of a Getting Involved Guide. If there's something the Drupal project can do to make their community more inviting to new contributors, I don't know what it could be.
Python: The well-known Python programming language has a large, friendly, active, diverse community behind it. Hawthorn recommends contributing to Python because the project offers supportive user groups and a Python Core Development Mentorship.
Jacob Kaplan-Moss, one of the lead developers of the Django Python Web framework, got his start with this project. "I was aware of open source before then, but Python was the first thing I ever felt motivated to contribute to," he says. Kaplan-Moss points out that, despite being a friendly and welcoming project with a mentorship program for new contributors, contributing to Python comes with a catch. "Python's quite mature, so the bugs that are left to be fixed tend to be difficult, obscure, and very much corner-cases," he says.
Whereas other projects have struggled to attract female contributors, Python offers a bit more diversity. In late 2012, the Python Software Foundation recommended that Python conferences create and apply a Code of Conduct, and the foundation no longer funds events without one in place. The Python community has an established Diversity Statement and offers financial aid to help first timers attend PyCon conferences.